Transcript Incidence and outcomes of LASIK free cap

Incidence and outcomes
of LASIK free cap
Tanguy Boutin, MSc, Eser Adiguzel, PhD, Avi Wallerstein, MD,
Mark Cohen, MD, Mona Harissi-Dagher, MD
The authors have no financial interest in the subject matter of this poster.
Background
Some of the most serious complications of LASIK are
linked to the use of the microkeratome.1 The flap can
be thin, irregular, buttonhole, incomplete or a
dislocated/free cap.
Possible causative factors are flat corneas, deep orbits,
inadequate suction, decentered ring placement, and
faulty microkeratome blades.2
Purpose
To determine the incidence, management,
and visual outcomes of LASIK free cap
following a microkeratome cut.
Methods
Retrospective observational case series of 183,941
consecutive LASIK surgeries between 2007 and 2010 in a
high volume refractive surgery setting, using
standardized equipment and techniques to determine
the incidence of intra-operative free cap.
Primary outcome measurements:
Manifest Refraction (MR)
Uncorrected distance visual acuity (UDVA)
Corrected distance visual acuity (CDVA)
Further corrective surgery was documented as well.
Results
7 eyes of 7 patients were indentified as having an intraoperative free cap out of 183,941 LASIK procedures
performed, resulting in an incidence of free cap of 0.004%.
Post-operative follow-up: 2 weeks - 27 months.
Four of the 7 eyes have long-term follow-up of over 6.5
months.
One patient did not have further laser correction, lost 2 lines
of UDVA and 1 line of CDVA with mild haze development.
Additional corrective surgery was performed in the other
three patients, at various times after free cap occurrence.
UDVA was greatly increased in those eyes. Only one eye lost
one line of CDVA.
Patient 1: 38 year old woman
Pre-op
Pre-op:
OD
OS
Manifest Refraction
-1.50D x -0.50D x 6°
-1.75D x -0.50D x172°
UDVA
20/60-1
20/60-1
CDVA
20/20+
20/20+
Keratometry
43.8D
43.3D
Comments:
OD treatment uneventful.
Free cap OS due to suction loss. Free cap replaced.
No laser treatment OS. 3 days post-op, free cap
found moved and became fixed in malposition.
19 months post-free cap
27 months Post-op :
Pre-op Values:
Manifest Refraction
Manifest Refraction
pl x -0.50D x 45°
-0.75D x -0.75D x 90°
UDVA
20/25-2
20/80-
CDVA
20/20-
20/25+2
Comments:
Mild haze and scarring
visible on cornea. No
additional laser treatment
performed
UDVA
CDVA
Keratometry
Comments:
27 mths Post-op Values:
Manifest Refraction
Patient 1: 38 year old female
OD
-1.50D x -0.50D x 6°
OS
-1.75D x -0.50D x172°
20/60-1
20/60-1
20/20+
43.8D
OD treatment uneventful. Free cap OS due to suction loss
OD
pl x -0.50D x 45°
20/20+
43.3D
OS
-0.75D x -0.75D x 90°
UDVA
20/25-2
20/80-
CDVA
20/20-
20/25+2
Further corrective surgery:
None
Patient 2: 26 year old man
9 months post-free cap (pre-enhancement)
Pre-op:
OD
OS
Manifest Refraction
-4.00D x -0.50D x170°
–4.25D x -0.75D x180°
UDVA
CDVA
CF
20/20
CF
20/20
Keratometry
41.0D
40.8D
Comments:
OD treatment uneventful.
Lost cap OS, PRK immediately performed.
9 months Post-op:
Manifest Refraction
plano
pl x -1.25D x180°
UDVA
20/20
20/30
CDVA
20/15-2
20/20
Comments:
Temporal, nasal, and
anterior scarring, with
clear central cornea
Additional treatment:
Corneal scrape + burr
9 mths post-op to treat
corneal scarring
None
F/U time
13 mths
Manifest Refraction
+1.25D x -1.75D x170°
UDVA
20/40
CDVA
20/20
Comments:
Traces of haze
22 months post-free cap (post-enhancement)
Patient 3: 30 year old woman
Pre-op
Pre-op :
OD
OS
Manifest Refraction
-4.75D x -0.25D x 154°
-4.50D x -0.25D x 178°
UDVA
CDVA
CF
20/15
CF
20/20+
Keratometry
44.7D
45.0D
Comments:
Tight orbits, micro-ring used, free cap OD.
Free cap replaced. No treatment OS.
2.5 months post-op:
Manifest Refraction
-4.25D x -0.75D x 125°
-4.00D x -0.50D x 5°
UDVA
CF
CF
CDVA
20/20-2
20/15-1
Additional laser
treatment:
PRK OU 2.5 mths post-free cap
F/U time
5 months
Manifest Refraction
pl x -0.50D x 146°
-0.25D sph
UDVA
20/25-2
20/20
CDVA
20/20
20/20
Comments:
Trace of haze
2 months post-free cap (Pre-PRK)
Patient 4: 31 year old man
Pre-op
Pre-op:
OD
OS
Manifest Refraction
-2.75D sph
-2.25D sph
UDVA
20/400
20/400
CDVA
Keratometry
Comments:
20/20
20/20
44.4D
46.0D
OD treatment uneventful.
Free cap OS due to possible suction loss. Free cap
replaced. No laser treatment OS.
3.5 months Post-op:
Manifest Refraction
+0.50D x -0.25D x 45°
-2.25D x -1.25D x 056°
UDVA
20/20-
20/200
CDVA
20/20-
20/20-
None
PRK 3.5 months
post-free cap
Additional laser
treatment:
F/U time
3 months
Manifest Refraction
+1.50D x -0.75D x 145°
UDVA
20/20-2
CDVA
20/20
3.5 months post-free cap (Pre-PRK)
Discussion
 The incidence of a free cap complication during LASIK was found to be
0.004% in a 3 year period while other studies have shown an incidence
between 0.01% and 1.31%.1,3,4
 Meticulous and precise repositioning of a free cap, using ink reference
marks, resulted in minimal loss of CDVA.
 The etiology of the causes of LASIK free caps are varied, from flat corneas
(K<42D), mispositioning of the microkeratome, suction loss, postintervention trauma, or unknown etiologies.2,5
 PRK has been used in cases of free cap complications in our group and others
resulting in improved UDVA.6
Conclusions
 Free cap is a rare intra-operative LASIK flap
complication.
 This study suggests that immediate and meticulous
repositioning of the cap without laser ablation is
most appropriate.
 PTK/PRK 3 months later is an appropriate
refractive surgical management.
References
1. Gimbel et al. Incidence and management of intraoperative and early postoperative
complications in 1000 consecutive laser in situ keratomileusis cases. Ophthalmology.
1998;105(10):1839-47.
2. Melki and Azar. LASIK complications: etiology, management, and prevention. Surv
Ophthalmol. 2001;46(2):95-116.
3. Lin and Maloney. Flap complications associated with lamellar refractive surgery. Am J
Ophthalmol. 1999;127(2):129-36.
4. Stulting et al. Complications of laser in situ keratomileusis for the correction of myopia.
Ophthalmology. 1999;106(1):13-20.
5. Slade SG. Lasik : Intraoperative (Flap) Complications. In: Alio JL and Azar DT, eds.
Management of Complications in Refractive Surgery. Springer, 2008; 15-31.
6. Utz and Krueger. Management of irregular astigmatism following rotationally disoriented
free cap after LASIK. J Refract Surg. 2008;24(4):383-91.